Western meadow vole

Suborder

The American Society of Mammalogists Mammal Diversity Database (MDD) currently places the species within the Suborder Supramyomorpha. This designation reflects the acceptance of recent large-scale molecular phylogenetic studies that reorganized the Rodentia into three major clades. The necessity for the new suborder arose because genetic analysis showed that the classical Suborder Myomorpha, which housed the mouselike rodents, was paraphyletic—it included the common ancestor but excluded certain descendant groups (like beavers and pocket gophers). Supramyomorpha is the larger, monophyletic group that includes the traditional Myomorpha and all of its descendants. The classification system recognizing Suborder Supramyomorpha was adopted in the paper Flynn et al. (2019), with the name formally proposed by D'Elía et al. (2019). We acknowledge that many regional checklists and traditional resources continue to use the more classical and recognizable Suborder Myomorpha.

Tribe

The genus Microtus was formerly included with Arvicola in the broadly defined tribe Arvicolini based on morphological similarity. Recent molecular genetic analysis (Golenishchev and Malikov, 2006) showed that the two genera are not “sister taxa.” In 2006, Microtus was moved to the new tribe Microtini, which now contains seven other genera, all sharing the derived trait of rootless, ever growing molars and crown cement. This site, however, adheres to the current classification of the American Society of Mammalogists Mammal Diversity Database, which retains Microtus within the tribe Arvicolini.

Species

A recent DNA analysis (Jackson and Cook, 2020) analyzed the mitochondrial DNA of all 28 subspecies of Microtus pennsylvanicus. The authors proposed separating Microtus pennsylvanicus into four distinct species. Under this arrangement, Microtus drummondii is the most widespread species. It subsumes fifteen former subspecies, and it is the only species occurring in Minnesota. It has been placed in the subgenus Pitymys and been given the common name western meadow vole.

Subgenus

The subgenus placement for Microtus drummondii is currently one of the most disputed areas of its classification. Historically, species like the Western Meadow Vole were placed in the subgenus Mynomes, based primarily on cranial characteristics. However, the recent molecular split by Jackson and Cook (2020) placed the resulting species, M. drummondii, into the subgenus Pitymys. The American Society of Mammalogists Mammal Diversity Database (MDD) continues to use the subgenus Mynomes for Microtus drummondii, a common practice among major authorities seeking to maintain stability while broader taxonomic revisions for the entire genus Microtus are finalized.

This site adheres to the current classification of the American Society of Mammalogists Mammal Diversity Database, which places Microtus drummondii in the subgenus Mynomes, retains Microtus within the tribe Arvicolini, and places the infraorder Myomorphi in the Suborder Supramyomorpha.